A number of technological applications involve the application of electromagnetic radiation to a target. For example, electromagnetic radiation may be employed for heating, drying, curing (as in photopolymerization), or the like. One such application involves curing a precursor layer present on the outside of an object to produce a polymer coating on the object surface. One object to which such a polymer coating is applied is an elongate glass fiber.
A number of attempts have been made in the state of the art for providing processes for applying electromagnetic radiation to a target, often based on placing the object to be treated at the focal point of a reflector and thereby focusing applied radiation at that point.
For example, in U.S. Pat. No. 8,604,448, a device is disclosed for curing a coating on a fiber using ultraviolet (UV) light. The device includes a cavity of elliptical cross section bordered by mirrors. The fiber to be cured is located at the focal point of the ellipse and the UV light is focused there to effect curing of the target.
U.S. Pat. No. 4,710,638 also discloses a device for curing a coating on a fiber using radiation. Again, the curing chamber includes an elliptical cross section bordered by mirrors. The radiation source is positioned at one focal point of the ellipse and the target at the other. In this way radiation is focused on the target at a point.
However, it would be desirable to provide improved devices and processes for applying radiation to a target, for example, in the field of curing coatings on glass fibers with different radiation sources.